In recent years, an effort to efficiently utilize energy has been made by using a secondary battery, such as a lithium ion battery, for a power supply mounted on a vehicle or a power supply for storing electricity in a smart house. However, it is known that characteristic deterioration of the secondary battery is caused by charge, discharge and storage thereof. Since it is assumed that the power supplies for the above-described uses are utilized over a long period of time, it is important to suppress the characteristic deterioration of the secondary battery.
As a means for suppressing the deterioration, it is effective to detect accurately deterioration states of a positive electrode and a negative electrode of the secondary battery and select an optimum using method for the battery according to the detected deterioration states. For example, PTL 1 describes a method in which deterioration states of a positive electrode, a negative electrode, and an electrolytic solution are respectively quantitatively evaluated in a non-destructive manner by utilizing a charging and discharging curve of a secondary battery. Further, NPL 1 discloses a method of calculating a discharging curve.